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This Report not to be guoted without prior reference to the Councilx) International Council for the

Exploration of the Sea

C.M.l982/Assess:l2

ATLANTO-SCANDIAN HERRING AND CAPELIN WORKING GROUP REPORT Part l

Copenhagen, 4-6 May 1982

This document is a report of a Working Group of the International Council for the Exploration of the Sea and does not necessarily represent the views of the Council. Therefore, it should not be quoted without consultation with the General Secretary,

x) General Secretary, ICES,

Palægade 2-4, DK-1261 Copenhagen K, Denmark.

TABLE OF CONTENTS

l, INTRODUCTION AND PARTICIPANTS l

1,1 Terms of Reference . , , • , , • , , , ••• , , , , , • , , , , , , , , , , l l, 2 Participants , ,-, , , , , •• , , • , , , • , , , •• , , • , , , , , , , • , , l 2. NORWEGIAN SPRING SPAWNING HERRING ••••••••••••••••••• l 2.1 Catch Statistics , • , • , , , , • , , , , , , • , , , , , , , , , • , , , • l

2.2

Autumn Fishery in

1981 ,,,,,,,,,,,,,,,,,,,,,,,,

l

2.3

By-Catches and Unreported Catches ,,,,,,,,,,,,,,

2 2.4

Larval Surveys in

1982 •••••••••••••••••••••••• 2 2.5

0-Group Investigations in

1981 ,,,,,,,,,,,,,,,, 2 2.6

Acoustic Investigations on the Spawning Grounds

in

1982 , , , , , , , • , . , , .. , . , . , . , . , . , . , . , . , . , , , , , . • 2 2.7

Tagging Experiments •••••••••••••••••••••••••••

2 2.8

Mortality Estimata •• , • , , , , •••• , • , , •• , •• , , •• , • ,

2 2.9

Abundance Estimates of the Spawning Stock ••••••

4 2.10

Virtual Population Analysis •••••••••••••••••••

5 2.11

Conclusion • , , •• , , •• , ••• , , • , • , ••• , ••• , , , , • , • • • •

5 3·

FAROESE SPRING SPAWNING HERRING ••••••••••••••••••••• 6 4• THE ICELANDIC SPRING AND SUMMER SPAWNING HERRING 6

4·1 4·2 4·3 4·4 4·5 4.6 4·7 5·

^THE

5.1 5.2 5·3 5·4

The Fishery , , •• , , , • , , , • , , , , , , • , , , • , , • , , • , • , , • • 6 Stock Abundance and Mortality Rates ,,,,,,,,,,,

7

The Catch in Number, Mean Weights and Age at

First Maturity , ••• , •• , , •• , ••••••• , ••••• , ••••• •

7

The Acoustic Ab.undance Surveys in

1981

and

January

1982 , , , , , , , , , , , , , , , , , , . , , , , , , .. , • , , . , , 8

The Fishing Mortality in

1981 ,,,,,,,,,,,,,,,,, 8

The Results of the VPA , , , , , , , , , , • , •• , , • , •• , • , • 9 The State of the Stock ••••••••••••••••••••••••

10

ICELANDIC CAPELIN

The Fishery during the

1981-82

Season ••••••••••

Estimates of Spawning Stock Abundance ,,,,,,,,, Abundance Estimates of 0-Group and Juvenile Capelin , , , , , , , . , .. , , , .. , .. , .. , ... , . , , , , . , , , , , , Present State of the Stock and Management Advice , , , •• , , , , , , , , , • , •••• , •• , ••• , • , •• , ••••• , •

lO lO lO 12

6.

IMPROVEMENTS OF THE DATA BASE ••••••••••••••••••••••••

6.1

Norwegian Spring Spawning Herring ••••••••••••••

6.2

Icelandic Summer Spawning Herring ••••••••••••••

6.3

The Icelandic Capelin • , , •• , •• , • , • , •••• , , ••••••

12 13 13 14 14

References

Tables 2.1 - 5,8 .. , •.... , . . . , . . . . • . . . • . . . Figures l - 8 •. , , ... , . , , . , , . . . . , , , , .. , . , . , .. , , , , , . , , , , ..

14

15

30-37

- l -

ATLANTO-SCANDIAN HERRING AND CAPELIN WORKING GROUP REPORT - PART l

l, INTRODUCTION AND PARTICIPANTS 1,1 Terms of Reference

The Atlanto-Soandian Herring and Capelin Working Group met at ICES headQuarters from 4-6 May 1982 in order to:

(i) assess the state of the Atlanto-Soandian herring stooks, and (ii) assess the state of the oapelin stook in Sub-areas V and XIV and advise on any neoessary management measure for that stook, Another meeting of the Working Group is soheduled to take plaoe from 27-29 Ootober 1982 to assess the state of the oapelin stook in Sub- areas I and II and re-assess the oapelin stook in Sub-areas V and XIV, 1.2 Partioipants

A Dommasnes Norway

J Jakobsson (Chairman) Ioeland H ! Jakupsstovu Faroes

p Kanneworff Danmark

V Ryzhov USSR

I Røt tingen Norway

s

Shleinik USSR

2. NORWEGIAN SPRING SPAWNING HERRING 2.1 Catoh Statistios

Table 2.1 gives the oatoh north of 62°N of the Norwegian spring spawners sinoe 1972, Table 2.2 gives the oatohes in number, For 3 year old and older herring unreported oatohes are inoluded.

2,2 Autumn Fishery in 1981

The total oatoh Quota of the fishery in 1981 was set to 100 thousand heotolitres (9 300 tonnes), Of this, 6o% (or 5 580 tonnes) was allooated to the seine fishery (land and purse seining), and 40%

(or 3 720 tonnes) to the gill-net fishery, The land seine fishery was opened 25 August, the purse-seine fishery 28 September, and the gill-net fishery 19 Ootober. The olosing date for all gear oategories was set at 21 Deoember. A minimum landing size of 25 om, with allowanoe of 15% undersized fish (in weight) has been in fore&. The same areas as in 1980 were olosed to fishing (Anon,, 198la).

The reported oatoh in the autumn fishery in 1981 amounted to 7 814 tonnes, The herring in the inner part of the Trondheimsfjord are assumed to belong to a looal stook (Anon., 1980), An additional oatoh of l 425 tonnes from this stook is not inoluded in Tables 2.1 and 2.2.

Table 2.2 shows that a relatively large amount of 2 year old herring (1979 year olass) was oaught in the autumn fishery. The reason for this was that in the Møre area, few adult herring were found outside the olosed area in Aure-Vinjefjorden, The reoordings of herring in Møre, at whioh the purse se1n1ng was aimed, oonsisted of smaller herring, mainly of the 1979 year olass,

- 2 - 2.3 By-Catches and Unreported Catches

Unreported catches may occur from various sources (Anon., 1981). The Working Group has earlier judged these catches to be approximately 10 000 tonnes. However, due to lower prices and saturation of the international herring market, it is reasonable to assume that the unreported catches have decreased in 1981, In Table 2.2 the extra catches for 1981 are, therefore, reduced to 5 000 tonnes.

By-catches of 0-group herring in the sprat fishery occur frequently.

Catches containing up to 50% of 0-group herring can be landed in the sprat fishery, However, the sprat fishery north of 62°N has decreased, Table 2.3 gives the catches of sprat and herring north of 62°N since 1978, together with the corresponding acoustic estimate of 0-group herring, The table indicates that the by-catches of 0-group herring are of secondary importance to the magnitude of the total mortality rate.

2.4 Larval Surveys in 1982

Figures l and 2 give larval distribution charts from April 1982, No increase in herring larvae has been observed since 1981. The temperature of the waters on the coastal banks north of 62°N is below average, and there may be some increase of herring larvae in May, From 15-18 April, a Soviet research vessel took 17 stations in the Norwegian shelf area, but no herring larvae were recorded.

2.5 0-Group Investigations in 1981

The results from the joint international 0-group survey in the Barents Sea show no increase in the abundance of 0-group herring in that area in 1981 (Anon., 198lb). An acoustic survey of 0-group herring distributed in the coastal area of Norway was conducted in November-December 1981. The estimate for 1981 is shown in Table 2.4, and it is of the same order of magnitude as in 1980, and indicates that the 1981 year class will be weak.

2.6 Acoustic Investigations on the Spawning Grounds in 1982

An acoustic survey was carried out on the spawning grounds of the southern stock component in February-March 1982, The results were not dealt with by the Working Group, but it is planned to submit a report of the survey techniques and the results to the ICES Statutory Meeting 1982. The survey will be repeated in 1983,

2.7 Tagging Experiments

The internal tagging project and experimental fishing for recoveries, as described in previous reports, have been continue~. In the winter ~

1982, 759 tonnes of herring were caught and screened for tags, and 104 tagged herring were recovered, Most of the catches were taken on the spawning grounds of the southern stock component.

2.8 Mortality Estimate

In previous years most of the experimental catches originated from the northern stock component, which is the largest one. The samples of recaught tags from that component were therefore used to estimate the total annual mortality rate in the tagged population, because the data from the southern component were not found adequate for a separate mortality estimate. Based on 83 recoveries obtained from catches taken in 1980-81, the Working Group estimated last year an average Z-value of 0.23 for the period 1975-78, This Z-value was then accepted as an average total annual mortality estimate of all tagged fish.

- 3 -

In 1982, the bulk of the catch and recoveries originate from the southern component. Details of releases and recoveries are given in the text table below:

Year of

re1ease m r ^K 1n K m82

1975 5000 2 25.0 3.22 999

76 3200 2 16.0 2.77 805

77 16044 12 13.4 2.59 5080

78 11998 8 15.0 2.71 4781

79 5995 9 6. 7. l . 90 3007

80 19994 23 8.69 2.16 12621

1981 15542 29 5.36 l . 68 12349

Sum 85 39642

m number released

r number of recoveries in winter 1982 K m/r • 10-2

m82 calculated number of surviving tagged fish in 1982, disregarding the initial mortality due to tagging.

The catch is estimated to contain l 406 x 103 herring effectively screened, The releases, recoveries and catches refer to the year classes older than the 1978 year class (5+).

The plots of ln K against time (in liberty) of releases are shown in the text figure below:

In K 3,5

3,0

2,5

2,0

z

=

0,23 r =-1-0,91

1,5 -L---..---.---....---.----r----r---r--.:::..,.--

197 5 1977 1979 1981

- 4 -

The plots yield an average Z for the years 1975-81 of 0.23, which is the same Z-value as calculated last year

Abundance Estimates of the Spawning Stock Southern component

Applying Z

=

0.23 as annual mortality rate of the tagged population, the state of the tagged population in 1982 is estimated and shown in the column to the right of the text table on p.3 (m82)• Assuming 30% tagging mortality, as in the previous report, the stock in number (N) for year classes older than 1978 (5+) in early 1982 is as follows:

N = 39 642x 0.70 x l 406 :x: 103 85

The percentage age distribution of the southern spawning component is derived from 7 samples drawn from the experimental catches, each sample containing 100 fish.

Year class 1979 1978 1977 1976 1975 1974 1973 1972 1969

% 19.0 15.2 16.8 25.1 6,4 10.8 6.0 0.2 0.5

Distributed on year classes according to the age distribution given above, the stock in number and weight in early 1982 is oalculated as follows (in million individuals):

Year c las ses

Year 1979 -78 -77 -76 -75 -74 -73 -72 -69 1978+ Tonnes x

1981 lO 131 209 37 78 57

o o

512 170

1982 133 107 117 175 45 77 42 l 3 567 190

The corresponding stock estimate in 1981 is included for comparison.

The estimates show that both the year classes 1977 and 1978 are weak, compared to the 1976 year class, whereas the 1979 year class is more _ promising. A slight increase in stock size (10%) is, however, observec also this year.

Northern component

The assessment of the state of the northern stock component in 1982 is based on the stock estimated in 1981 and the age composition of the spawning stock component in 1982. The percentage age distribution is derived from two samples (200 fish) drawn from catches taken of pre-spawners in the Lofoten area in February 1982 and given in the text table belo1<r:

Year class 1978 1977 1976 1975 1974 1973 1972 1969

% 16 3 14 ² 19 40 l 5

103

Year 1981 1982

- 5 -

In the text table below are given the stock estimate in number (in million individuals) by year classes obtained in 1981 (Anon,, 1981) and the calculated stock number in 1982, assuming that all age groups older than the 1976 year class were fully recruited in 1981, In this caloulation, a Z-value of 0.2 vras used:

Year classes

1978 -77 -76 -75 -74 -73 -72 -71 -69 l l978+•''Tonnes x lo-3 7 86

121 23 106

21 157 343 15 144 303

7 8

7

o

86 714 38; 758

270 290 The estimate indicates a slight inorease in the spawning stock size due to the somewhat better reoruitment from the 1978 year olass than from the year classes 1975-77•

2,10 Virtual Population Analysis

A VPA has been run, using the following input data:

Catoh in number per year class: Tab le 2.2

Weight at age: Tab le 2.5

Natural mortality: 0,18

Maturation coefficients: 3 years old 4 years old 5 years old 6 years old Terminal F (1981) for eaoh year class:

NDec 1981 01981

e -Z

O.l 0.8 0.9 LO

NDec 1981

=

Nspring 1982 found in the tagging experiment.

Table 2,6 gives the fishing mortalities and Table 2,7 the stock size from the VPA run. The latter shows that the spawning stock increased from 84 000 tonnes in 1973 to about 400 000 tonnes in 1978, During the last three years (1979-81) the spawning stock has been at the level of about 460 000 tonnes,

For the spawning stock, the estimates from the VPA show the same general trend in 1977-80 as the results from the tagging experiment, i.e., an increase of approximately 150 000 tonnes. The estimate for eaoh year is, however, somewhat higher in the VPA, This is

especially true for the 1973 year class, 2,11 Conclusion

The spawning stock of the Norwegian spring spawners oonsists of two oomponents. The assessment of the southern stock component in 1982 is based on the results of the internal tagging projeot. From 85 recoveries of tagged herring, a total average mortality of 0.23 for the years 1975-81 was estimated for the tagged part of the popu- lation, Combined with oatch data from the experimental fishery,

- 6 -

the abundance of the total southern stock component in 1982 was estimated to be 190 000 tonnes,

The assessment of the northern stock component is based on the stock estimata from 1981 and the age composition in 1982. This gave an estimata of 290 000 tonnes for the northern stock component in 1982,

Thus, according to the present assessments, the overall abundance of the spawning stock of Norwegian spring spawning herring is estimated to be in the order of 450 000 - 500 000 tennes. The catch in 1981 is estimated to be 15 000 tennes, in which an assumed unreported catch of 5 000 tennes has been included. This catch generated a fishing mortality of about 0.03 in 1981, Despite this low fishing mortality, there has only been a slight increase in the spawning stock abundance in recent years. This is due to the small recruitment to the spawning stock of two weak year classes, i.e,, 1977 and 1978, A certain increase is

expected in 1983, "l'rhen the 1979 year c lass 1vill begin to recrui t to the spawning stock, However, according to the 0-group estimates, the 1980 and 1981 year classes are poor. The overall abundance as well as recrui tment are still at a very lo"l'r leve l compared to earlier periods, The Working Group, therefore,

recommends that the stock should be rebuilt to a much higher level, The rate of recovery will of course be maximized, if no fishing is allowed, However, if a fishery is conducted, care should be taken that such a fishery only generates a very low fishing mortality. The Working Group does stress that if the present 1evel of exploitation rate is exceeded, this may stop any further rebuilding of the stock.

3· FAROESE SPRING SPAWNING HERRING

In contrast to the three previous years, in 1981 no by-catch of spring-spawning herring was reported from the trawl fishery on the Faroe Plateau. Furthermore, in the Faroese 0-group survey in 1981 no 0-group herring were caught,

The traditional spawning grounds were surveyed in March 1982 by the Faroese research vessel "Magnus Heinason", using sonar and echo-sounder in addition to extensive bottom trawling, The result was totally negative, From this the Working Group notes that the small component cf spring-spawning herring present on the Faroe Plateau in the years 1978-80 now seems to have vanished,

4• THE ICELANDIC SPRING AND SUMMER SPAWNING HERRING 4.1 The Fishery

No signs of recovery of the Icelandic spring-spawning herring have been observed, and the fishery in 1981 was entirely based (99.9%) on Icelandic summer spawners.

The landings of summer-spawning herring from 1971 to 1981 are given in Table 4.1. The .1981 landings were about 39 100 tennes.

The catches with purse seine and drift nets are shown in the text table below. It should be noted that the purse-seine figures include 650 tennes, which were taken in January 1981,

- 7 -

while the remainder of the catches were taken during the main season September to December 1981, The drift-net landinga include l 622 tonnes taken by set nets.

Landings and TACs in tonn es (x 10- 3 ) of Icelandic

Year 1978 1979 1980 1981

summer spawners 1978-81

Purse seine Drift nets Total

Catch TACs Catch TACs Catch TACs Rec.TACs

20.2 20.0 17.0 15.0 3 7. 3 35.0 3 5.

o

25.5 20.0 19.6 15.0 45.1 35.0 35.0

32.6 3 2.

o

20.7 18.0 53.3 50.0 45.0

21.3 22.5 17.8 18.0 39.1 42.5 40.0

It is noted that about 5% of the set TAG was not taken, This was due to the fact that owing to the difficult market situation, 12 of the purse seiners did not use their allotted quota.

4.2 Stock Abundance and Mortality Rates

The assessment of the stock and the exploitation for 1981 is, as in previous years, based on an acoustic stock abundance estimate and catches by age using a VPA.

4·3 The Catch in Number, Mean Weights and Age at First Maturity

Weight in g

The catches in number by age for the Icelandic summer spawners are given in Table 4.2 for the period 1969-81, As in 1979 and 1980, the catches in 1981 were predominated by the 1974 and 1975 year classes (Table 4.2). It should be noted that the strong year class from 1971 has contributed about 9% to the catch during the two last years. As stated in last year's report of the Working Group, the echo-abundance estimates in December 1980 gave very high values of l- and 2-ringers (1978 and 1977 year classes), It was, therefore, expected that 3-ringers would in 1981 be in high proportions in the catch that year. This, however, was not the case, as shown in Table 4.2, because 3-ringers made up about 12% of the catch instead of the expected 30%.

The weight at age in grammes is given for each year in Table 4.3 and is used for calculating biomass. During the period 1974-79, there was a clear trend in declining mean weights, especially in the younger part of the population, Thus, the mean weight of 3-ringers were:

1978 1979 1980 1981

262 241 243 217 196 182 202 186.5

- 8 -

After a declining trend in the mean weights of 3-ringers, there was an increase in 1980, Due to very low mean weights of 2-ringers in 1980, it was expected that the mean weights of 3-ringers in 1981 would be very low indeed, As shown in the text tab le on p, 7, the mean \veights of 3-ringers in 1981 were at the same level as in 1978 and 1979 but not as low as expected.

During the period of lmv abundance of the stock, 95% - 98% of the 3-ringed herring were mature and spawned at that age, In the period 1979-81 about 30% - 50% of the 3-ringed herring in the catches were mature. In 1981, about 6o% of the 3-ringed herring in the catches v1ere mature, This was a much higher portion than expected on the basis of last year•s samples, During the period of high abundance of the stock in the 1960s, about 50% of the 3-ringers v1ere mature,

4.4 The Acoustic Abundance Surveys in 1981 and January 1982

As in 1980, the main herring fishery took place in the east coast fjords in 1981, but when the acoustic abundance surveys started about mid-November 1981, the major part of the herring concentrations had emigrated from the fjords, Repeated surveying until mid-December revealed some herring very close to the shore at southeast and south Iceland, but acoustic estimates could not be obtained in that area,

By 20 December some herring had assembled at southwest Iceland near the mouths of the two main rivers: Olfusa and Thj6rsa, an acoustic abundance estimate was obtained, and according to this about 50 000 tonnes of herring had assembled in that area, During the period 9-10 January, the acoustic abundance estimates in the southwesterly area were repeated under excellent weather con- ditions (Figure 3).

Based on TS values for the various length categories obtained in 1980 as well as a few new estimates obtained in November and December 1981, the following e~uation was used to convert the echo abundance into fish abundance:

C = 13,0 X 1-2 •1 7 X 106

where C is the density coefficient and l is the length of the fish in cm, The value used corresponds to a TS of -34.6 dB/kg for 20 cm herring weighing 55 g, and a TS of -36.5 dB/kg for 30 cm herring vleighing 205 g.

Using the e~uation as well as the length and age distribution in the samples taken on the wintering grounds at southwest Iceland, an estimate of the number of herring in each age group was obtained (Table 4.4). Based on the mean weights at age from the sampling of the wintering concentrations, these numbers correspond to a biomass of about 200 000 tonnes of herring, It is clear from the age distribution in Table 4.4 that the immature l- and 2-ringers were more or less absent on the new wintering grounds in January 1982, Despite echo surveying in several of the north and east coast fjords in November and December 1981, these immature herring were only located in very low numbers. There is thus an uncertainty about the recruitment to the Icelandic summer-spawning stock in the near future.

4.5 The Fishing Mortality in 1981

As in previous years, the fishing mortality for 1981 was calculated

N

- 9 -

from the survey results as given in the text table below and from the oatch data from the previous fishing season, using the eQuation with M = 0,1:

Rings 81/82

0/1 1/2 2/3 3/4 4/5 5/6 6/7 7/8 8/9 9/10 10/ll 4+

2 051

w

N -Z

Jan. 1982

=

^e

c1981 Cl-e-Z) F

z

Catch in no. Echostock in millions in millions

1981 Jan. 1982

5

2. 2 23

4.6 99

16.7 206

12.1 54

36.8 157

41.9 205

7. 3 30

4.8 lO

13.4 57

2.8 12

119 525

237 g Weighted mean F4+ 0.20

F 1981 0.0 0.09 0.04 0.08 0.20 0.21 0.18 0.21 0.38

o.

20 0.21

4.6 The Results of the VPA

A VPA was run, using the mean F for adult herring = 0.20 obtained from the catoh in number data in 1981 and the results of the eoho-abundance survey as desoribed above using M = 0.10. The results are given in Tables 4·5 and 4.6.

The present VPA gives somewhat higher stook estimates for the earlier years than that estimated in the VPA in the 1981 report, This is due to lower F values for adult herring in 1981, which in turn result from a somewhat higher aooustio estimate of the adult stook in January 1982 than in Deoember 1980, It should be noted that the herring were oon- fined to narrow fjords in 1980, where aooustio surveying and

espeoially sampling were muoh more diffioult than on the wintering areas in 1982. It is now evident that the younger herring were overestimated in the 1980 survey and the adult herring correspondingly underestimated, The present acoustio estimate is in line with the estimate given in the 1980 report.

The fishery on this stook was re-opened in 1975, and according to this new assessment, the fishing mortality for 4 years and older herring was about 0.15 for the first 2 years, During the 5 last years (1977-81), the fishing mortality has been about or just above 0.2. As shown in Table 4,6 the 1971 year olass is now estimated to have been about 495 x lo-6 as 1-ringers. The 1972 and 1973 year olasses are both weak (124 and 186 millions), while the 1974 and 1975 year classes are estimated to have been 685 and 493 millions as 1-ringers,respectively.

The 1976 year olass is poor, or only about 142 millions. The estimates of the 1975 and 1976 year classes are oonsiderably higher aocording to this new VPA than in that of last year. At that time very high estimates of the 1977 and 1978 year olasses were obtained from the

- lO -

acoustic survey. These year classes have not turned up in the catch in the same degree as expected, nor have they been located in great abundance during the echo-abundance surveys. The input F for those year classes was, therefore, adjusted to generate year classes of about 400 million herring as 1-ringers.

4·7 The State of the Stock

Based on the echo-abundance estimates from January 1982 of 5-ringers and older, and assuming that 3- and 4-ringers will be of average strength, the adult stock (3-ringers and older) will be about 290 000 tonnes in 1982, Of this adult stock biomass, about 60 000 tonnes are 3-ringed herring, In recent years only about half of the 3-ringers have reached maturity and contributed to the spawning stock. The spawning stock will, therefore, probably be about 260 000 tonnes in 1982. This level of stock abundance is within the range of stock biomass during the 1954-63 period of high and steady recruitment.

During the last few years, the fishing mortality in the adult component of the stock has been about, or just above, 0.2. The Working Group recommends that the exploitation of this stock should be continued at this level. On this basis, the Working Group recommends that the TAC for the Icelandic summer spawners for 1982 should be 50 000 tonnes.

5· THE ICELANDIC CAPELIN

5.1 The Fishery during the 1981-82 Season

The season opened in August, and before the end of the month Norway had taken her share of the preliminary catch ~uota of

700 000 tonnes she had bilaterally agreed upon with Iceland. From then on, the fishery was conducted by Iceland, the Faroes and vessels from EEC countries, mainly Danish.

Although Icelandic vessels started fishing for capelin already in August, they took their catch mainly in October and November, Iceland allowed only a very limited fishing in December 1981 as well as during the 1982 winter season, Faroese and EEC vessels mainly took their catch in August and September,

The monthly catch from the Icelandic capelin stock in weight and number during the summer/autumn 1981 and winter 1982 season is given in Table 5.1. The annual catch by nations and seasons from 1981-82 is given in Table 5.2.

5.2 Estimates of Spawning Stock Abundance

As described in a previous Working Group report, the size of the adult component of the Icelandic stock of capelin has since 1978 been estimated twice annually by acoustic methods, For each spawning stock (1979, 1980, 1981 and 1982) a first estimate has been obtained in October/November, and a second one in January/

February in the following year. Estimates yielding suspiciously low results,due to extensive drift ice, weather and the behaviour of the fish, were repeated as soon as possible afterwards, Furthermore, several estimates have been repeated 2-3 times both in autumn and winter in order to test the reliability of the acoustic method. Under normal working conditions, deviations

- l l -

within such sets of observations have been small (Vilhjalmsson et ~' 1982).

On 28-30 October 1981 the Atlanto-Scandian Herring and Capelin Working Group met in Copenhagen in order to assess the state of the Barents Sea and Icelandic capelin stocks. A joint Norwegian-Icelandic acoustic abundance survey of the Icelandic stock of capelin had then just been completed, The conditions during that survey had been far from ideal in that drift ice covered possible distribution areas, and clearly some of the stock had not as yet returned to its over- wintering grounds in Icelandic waters,

The resulting stock abundance estimate was very low or only 144 000 tonnes, counting all year classes. While it was realized that the October estimate most likely was unrealistic, it was accepted as a strong indication of low stock abundance.

In addition to the Atlanto-Scandian Herring and Capelin Working Group report from October 1981, the following survey results as well as catch in numbers and weight for the 1981-82 season were available to the present Working Group meeting for a new assessment of the state of the 1982 spawning stock of the Icelandic capelin:

L R/V "Bjarni Sæmundsson¹¹ NVl- and N-Iceland, 3-ll November 1981, Stock abundance in number and weight is given in Table 5·3·

During this survey there was much less drift ice than in October, the distribution area was smaller, and the weather was good.

2. R/V ¹¹Bjarni Sæmundsson¹¹ N- and NE-Iceland, 26-29 November 1981.

Stock abundance in number and weight is given in Table 5.4.

During this latter survey, reasonably good weather prevailed, and since the distribution of the stock was knmm due to previous surveying and information from the fishing fleet, it could be completed in a very short time.

As regards the mature stock component, there is very little difference between the abundance estimates derived from the two November surveys when account has been taken of the catch during the intervening period, (Table 5.8,)

The November estimates of stock abundance correspond to about 450 000 tonnes of spawning stock that should have been obtained in October had conditions been normal.

3. A third abundance estimate was obtained during ll-22 January 1982 by R/V "Bjarni Sæmundsson¹¹ and R/V "Arni Fridriksson"

off E- and SE-Iceland. Stock abundance in number and weight is given in Table 5·5·

Weather conditions presented certain difficulties, because much time had to be spent in vrai ting for a favourable oppor- tunity, This waiting was rewarded, but a further survey in February showed that spa\mers recorded off NE-Iceland at that time (Table 5.6) had not been included. This capelin must be added to the January acoustic estimate of the 1982 spawning stock, which then becomes as shown in Table 5·7•

When account has been taken of the November-December catches (Table 5.8) as \'lell as of natural mortality, the January-February estimate agrees with both those of November 1981, It is, therefore, concluded that all three estimates represent reliable evaluations of stock abundance at the times when they were obtained.

- 12 -

The results of the acoustic autumn and winter estimates of the abundance of the mature stock component for the period October 1978 - January 1982 are shown in Figure 4· It has been calculated, that, when account has been taken of the catch during the intervening period as well as of natural mortality, the difference between the two sets of stock abundance estimates does not exceed 5-lo%. This is illustrated in further detail in Figure 5, With the exception of surveys, which have be en vrrongly timed vri th re gard to the behaviour pattern of the fish or ice conditions, the results are remarkably consistent. They are, therefore, considered reliable and show an alarming decline in stock abundance,

Abundance Estimates of 0-Group and Juvenile Capelin 0-group abundance

Comparative measurements of the abundance of 0-group capelin have been obtained in August annually since 1972 (Figure 6), During the period 1972-75 the 0-group index indicates a high level of recruit- ment vrhich is follovred by .a downward trend and a distinctly lower level during the last 5 years, This development coincides with the large increase in fishing effort and catch as well as the change in fishing pattern brought about by the recent multinational summer and autumn fishing (Figure 7).

Abundance estimates of l-2 group juveniles

As yet it has proved difficult to assess the relative or absolute abundance of the l-2 group juvenile stock component, mainly because of its frequent distribution in or near areas that are impassable due to drift ice for long periods of time,

During the first half of November 1981 2.7 and 1.4 x 109 fish

belonging to the 1980 and 1979 year classes, respectively, were recorded (Table 5.3). At the end of the month a shoal of capelin belonging to the 1980 year class was further located off NE-Iceland (Table 5.4), bringing the total for that year class to 23.7 x 109 fish.

In February 1982, an acoustic survey covering the area off NW-, N- and NE-Iceland was carried out. This survey was fairly extensive and specially aimed at immature capelin of the 1980 and 1979 year classes.

The abundance estimate thus obtained is given in Table 5,6, It should be noted that part of the possible area of distribution could not be reached due to drift ice and weather.

Based on the results of acoustic surveying, the best approximation of the abundance of the 1980 year class is 23.7 x 109 fish obtained during the two November survey~, and for the 1979 year class the February 1982 figure of 4.3 x 10 fish. In spite of doubts as to the accuracy of the above figures, they should be interpreted as a strong warning of low abundance,

5·4 Present State of the Stock and Management Advice

Because of the very high spawning mortality, the main management objective is to prevent the spa;ming stock being reduced to a level which would cause reduced recruitment.

In 1979, when fishing was stopped in the third week of March, about 600 000 tonnes were left to spawn according to acoustic estimates of stock size, when account had been taken of fishing mortality and natural mortality,

- 13 -

In 1980 it was decided that, while gaining further experience, it would be inadvisable to reduce the spawning stock to less than 400 000 tonnes. To keep the spawning stock at this level has been the main management objective in the last three years, As shown in Figure 5, the spawning stocks in 1980, 1981 and 1982 have in fact been reduced to about 300 000 tonnes, 160 000 tonnes, and 140 000 tonnes respectively, as calculated from the winter acoustic surveys.

It is, therefore, clear, that the management objective has not been obtained in any of the years 1980, 1981 and 1982, The available series of data on stock/recruitment relationship is still too short to pinpoint the minimum amount that must be allowed to spawn in order not to reduce recruitment for that reason, but the data since 1980 indicate that it is inadvisable to have a spawning stock smaller than 400 000 tonnes.

During the last 2-3 years, the abundance of the Icelandic capelin stock has declined at an alarming rate, as indicated by the 0-group indices and the acoustic estimates. This, as well as the catches, are shown in Figure 8, Insufficient amounts have been left to spawn and the stock has been overfished. At present, the main management objective must therefore be to rebuild the stock to its previous level of abundance. In order .to achieve this objective, a much larger spawning stock must be preserved than during the last three seasons or not less than 400 000 tonnes.

Although 0-group indices cannot at present be used as a basis for TACs, a tentative indication of the relative size of each year class appears from that series of data, As shown in Figures 6 and 8, the 1980 year class is at a low level of abundance as judged from the 0-group results.

Reliable and comparable Quantitative data on the l- and 2-ringers, which make up most of the immature stock, have also proved difficult to obtain before they enter the fishery. Nonetheless, survey results in November 1981 yielded approximately 120 000 tonnes of immature capelin of the 1979 and 1980 year classes (Tables 5·3 and 5.4). If no fishing is conducted during the 1982/83 season, this indicates that the spawning stock in 1983 will be below 300 000 tonnes.

Although the above preliminary abundance estimate for the 1983 spawning stock cannot be considered accurate, it should not be ignored, Together with the 1980 0-group index it must be interpreted as a strong indication of a very low level of stock abundance, a continuation of the trend observed in the last four years (Figure 8), For the 1982/83 season a complete fishing ban is, therefore,

recommended, until a new and reliable estimate of stock abundance is available,

In October 1982, Iceland and Norway have planned an acoustic survey on the distribution and abundance of the 1983 spawning stock, Depending on the results of this survey, further management advice will be given,

6, IMPROVEMENTS OF THE DATA BASE

In accordance with C.Res.l98l/2:27:15, the Working Group discussed various deficiencies in the data base and how these could be improved.

6.1 Norwegian Spring-Spawning Herring

The Working Group noted that a considerable proportion of the estimated catch is not reported in the official statistics, If these catches were reported, this would greatly improve the assessment based on fishery data (VPA),

- 14 -

It was also noted that information on by-catches of 0-group herring in the sprat fishery came from sales organisations and not from scientific sampling, However, the sprat catches north of 62°N have been decreasing recently and, therefore, the herring by-catches in this fishery are at the moment of secondary importance, but this could change if sprat catches increased again. Therefore, a sampling programma is needed for this fishery.

The Working Group appreciates that in 1982 an acoustic abundance survey of the spawning component was conducted. It is recommended that further attempts should be made to obtain an acoustic

estimata of the stock,

6.2 Icelandic Summer-Spawning Herring

The Working Group recommends that acoustic surveys should be crarried out to cover not only the adult herring but also the younger, immature herring,

6.3 The Icelandic Cape1in

The Working Group strongly recommends that acoustic surveys on the l- and 2-group capelin should be carried out in order to get an estimata on the recruiting year classes early enough in the year to make it possible for the Working Group to carry out an assessment prior to the start of each fishing season.

It is also suggested that both the data handling as well as the 0-group survey design should be reconsidered, thus attempting to obtain a better estimata of the year class strength already at the 0-group stage.

The Working Group noted that catch statistics with catch in numbers by age groups were supp1ied by two countries (Norway and Ice1and).

It is, however, clear that such basic data must be supplied by all countries participating in the fishery.

REFERENCES

Anon., 1980, Report of the Atlanto-Scandian Herring Working Group, BergeR, 12-14 May 1980. ICES, C,M.l980/H:8.

Anon., 198la, Atlanto-Scandian Herring and Capelin Working Group report.

Part l. Copenhagen, 12-14 May 1981, ICES, C,M,l981/H:ll.

Anon., 1981b. Preliminary report of the International 0-Group Fish Survey in the Barents Sea and Adjacent Waters in August-September 1981, ICES, C,M,l981/G:78,

Anon., 1982, Atlanto-Scandian Herring and Capelin Working Group Report, Part 2. Copenhagen, 28-30 October 1981, C.M.l982/Assess:2.

Vilhjalmsson, H, Reynisson, P., Hamre, J, and I Røttingen, 1982, Acoustic abundance estimation of the Icelandic stock of capelin 1978-82.

Symp. on Fisheries Acoustics, Bergen 1982, Doc, No.21.

- 15 -

Tab1e 2.1 Catches north of 62°N of Norwegian Spring Spawning herring (tennes) since 1972.

Year

1972 73 74 75 76 77 78 79 80 81 1982

Catches of a~ult l) herring in Wlnter

o

139 906 53

o

374 484 691 878 844 983

Mixed herring 2) fishery in autumn

9895 6602 6093 3372 247 1.1834 9151 1866 7634 7814

l) Mostly experimental fishing

Bycatches of O-and I-group herring in the sprat fishery

3266 3 ) 276 620 288 189 498 189 307 65 78

2) Includes also bycatches of adult herring in other fisheries 3) In 1972 there was also a directed herring 0-group fishery

- 16 -

Tab le 2.2 Catch in numbers, mi11ions, Norwegian S~ring Spawners.

Unreported catches are included for 3 years and older herring.

Age 1972 1973 1974 1975 1976 1977

o

347.100 29.300 65.900 30.600 20.100 43.000

l 41.000 3.500 7.800 3.600 2.400 6.200

2 20.400 l . 700 3.900 l . 800 l . 200 3.100

3 35.376 2.389 0.100 3.268 23.248 22.103

4 3.476 25.220 0.241 0.132 5.436 23.595

5 3.583 0.651 24.505 0.910 0.000 0.336

6 2.481 l . 506 0.257 30.667

o.ooo o.ooo

7 0.694 0.278 0.196 0.005 13. 086 0.419

8 l . 486 0.178 0.000 0.002

o.ooo

10.766

9 0.198 0.000

o.ooo

0.000 0.000

o.ooo

lO 0.000 0.000 0.000 0.000

o.ooo o.ooo

11 0.494 0.000 0.000 0.000 0.000 0.000

12 0.593 0.000

o.ooo o.ooo

0.000 0.000

13 0.593 0,000 0.000 0.000

o.ooo

0.000

14

o.ooo

0.178

o.ooo

0.000

o.ooo

0.000

Age 1978 1979 1980 1981

o

20.100 32.600 6.900 8.300

l 2.400 3.800 0.800 1.100

2 l . 200 l . 900 0.400 11.900

3 3,019 6.352 6,407 4.166

4 12.164 l . 866 15.814 4.591

5 20.315 6.865 2.278 8.596

6 0.870 11.216 8.165 2.200

7 0.000 0.326 15.838 4.512

8 0,620 0.000 0,441 8.280

9 5.027 0.000 0.008 0.345

lO 0.000 2.534 0.000 0.103

11 0.000

o.ooo

2.688 0.114

12

o.ooo

0.000 0.000 0.964

- 17 -

Table 2.3 Catches of sprat and small herring since 1978 in the area north of 62°N

Year

1978 79 80 1981

l)

l

: 0-group acoustic Catch (tonnes) estimate (tonnes) Sprat By-catch of

herr ing l)

2445 189 6424

1350 307 20058

1050 65 1870

420 78 2092

Most of the by-catch is 0-group. Approximately 95% of the by-catch of herring is utilized by the canning industry. Because of the size, I and II- group herring cannot be utilized for this purpose.

Table 2.4

Year

- 18 -

Norwegian Spring Spa'\•mers. Abundance of 0-group herring in 1975 - 1980 (N x 10-6)

Area

Total 62°N - 65°N 65°N - 68°N North of 68°30'

1975 328 692 55 1075

76 415 2610 750 3775

77 70 305 37 412

78 302 511 392 1205

79 909 2260 288 3457

80 12 4 218 234

1981 262 2 l 265

- 19 -

Table 2.5 Average weight at age in grammes, Norwegian Spring Spawners, 1973-1981.

Yearc1ass

Age 1973 1974 1975 1976 1977 1978 1979 1980 1981

3 170 181 181 181 180 178 175 170 170

4 259 259 259 259 294 232 283 224 204

5 342 342 342 342 326 359 347 336 303

6 384 384 384 384 371 385 402 378 355

7 409 409 409 409 409 420 421 387 383

8 444 444 444 444 461 444 465 408 395

9 461 461 461 461 476 505 465 397 413

10 520 520 520 520 520 520 520 520 453

11 543 543 543 543 543 551 534 543 468

12 412 412 412 412 500 500 500 512 512

Table 2.6 Ca1cu1ated fishing morta1ity, Norwegian Spring Spawners, 1973-1981, H

=

0.18.

Yearc1ass

Age 1973 1974 1975 1976 1977 1978 1979 1980 1981 3 0.124 0.008 0.079 0.022 0.041 0.024 0.014 0.034 0.017 4 0.071

o.

013 0.010 0.176 0.027 0.028 0.019 0.041 0.030 5 l. 026 0.090 0.075 0.000 0.013 0.029 0.019 0.028 0.028 6 l. 896 2.329 0.152

o.ooo o.ooo

0.048 0.020 0.028 0.033 7 2.500 2.289 0.476 0.088 0.051

o.ooo

0.020 0.034 0.019 8 2.138 0.047 0,116 0.076 0.095 0.098

o.ooo

0.032 0.022 9 0,038 0.047 0.060 0.076 0.100 0.057

o.ooo

0.002 0.030 10 0.038 0.047 0.060 0.076 0.100 0.134 0.036 0.000 0.030 11 0.038 0.047 0.060 0.076 0.100 0.134 0.188 0.048 0.030 12 0.047 0.047 0.060 0.076 0.100 0.134 0,188 0.285 0.022 l\verat}e

F(4-lL:)0.086 0.090 0.142 0.094 0.035 0.031 0.020 0,035 0.025

Tab le 2

·l

^VPA. Norwegian spring spa..,.mers. Stock, 3 years and older, and spawning stock, in millions. ~1 =

o

.18.

Age

Age 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982

3 22 13 47 1169 603 136 515 211 272

4 400 17 l l 36 955 483 111 424 170 223

5 l 311 13 9 26 776 392 91 340 138

6 2 238 l l 8 21 630 321 74 276

7 170 9 6 17 516 261 59

8 130 7 5 14 416 214

9 99 5 4 l l 340

lO 78 4 4 9 ^1\) _o

l l 63 4 3

12 50 3

13 41

Total 425 341 309 1395 1731 1528 1753 1648 1602

Spawning stock 325 295 263 335 995 1232 1229 1366 1289

Spawning stockl) 84 99 99 105 310 406 462 472 450

l) Stock in weight in 1000 tonnes

'l'ab1e 4.1

- 21 -

Landings of Icelandic summer spawning herring 1972 - 1981 in tonnes x 10-3

1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 0.3 0.2 1.2 12.8 17.8 28.7 37.3 45.1 53.3 39.1

'l'ab1e

4·2 ^Catch

ⁱⁿ

numbers, mi11ions, Ice1andic Summer Spawners 1969 - 1981.

Rings 1969 19?0 19'71 1972 1973 1974 1975

4.520 2 ^{+ 00~~} B, '?74 o. 1?6 0.001 o.oo1 1.465

:~~ 78.410 22 + :~44 1:1.071 o' ^~~85 o. 1'72 3.t'>B1 1.9'77 3 a.274 33,965 5.439 o. 1.57 0.?34 o.~:n4 30.855 4 ::;. 178 4.500 13.688 O .1 S'5 0.113 0.972 6.266

~5 10. 01!'.'i 2.734 3.040 0.316 0.018 0.090 7.628 6 2.841 4.419 1. !'.'i63 O,O::'i6 0.014 0.045 0.833 7 1.389 l .14::'j 3.271.> 0.033 0.006 0.002 0.42'7 B :1..179 (), :531 0.748 0.029 0.006 o.oot o. 3~53

'7' 0.609 0,604 0.2ti0 0.016 o.oo3 o.oo1 0.110 10 0.424 o. :1.9::'i 0.:1.03 0.01.1 0.003 o.oot 0.004 :L1 0.286 o .1 o~~ 0.120 0.004 0.001 0.001 0.001 1" .... o ^.1:~9 (),076 0.001

o.oot

0.001. o.oo1 0.001

1"1 ~l o. 109 0.061 O,OOl 0.004 0.001 (),()01 o. ()(jl

1.4 0.074 0.051. 0.001 (),()01 0.001 o.oo1 0.001 t)UM 1.-- 2 B2.930 ^{:;;~4 +} 34/' 21.845 (). ~'.i61

o.

1'7:3 3.682 3.442

~)UM ~~ .. - .14 ~!,0. ::'ill 48,384 28, 2:W 0.823 0.901. 1.930 46.460 TDTf.1l.. 1L3,•147 72.731 :=:;o.o?:=i 1.:.384 1.074 t3 ^f 612 49.902

Rings 1976 1.9"l"i' 1978 1979 1980 1981

(),C),':Q O, Ml~~ 2.60? 0.919 3. 2:~9 2.279

2 10.136 18.266 ^{~~2 t} :us 1.4.•n2 14.768 4.622

~5 4.o::!2 23.400 !'.'i0.469 47. ^o:~s 21.370 16.?45 4 35.1.42 10.080 13. "/0~~ 68.968 62.509 12.107

J::'

~' /.21.4 44.913 8.648 16.270 67.245 36.813 6 ~:; + 641 6 + ~j:~5 :39 ^T Of~::'! 7. 91.5 11, B79 41.851 7 1 ⁺ 07,':, 5*252 7, 1./B 25. "7~i3 9.~i57 7.288 8 0.451 1.3~i2 6,28B 3.016 20.01.2 4.855 9 o. :3o~~ 0.508 ^1. ,597' 1.,f.l48 1. .fJ4<ii 13.395

lO 0.1.3B o. :_3~'j1 0.916 0.489 :1..507 1..030

1.1.

o,

^{o·;;~:i (),()26} 0.396 o ^t 4~~4 0.71.8 0.883 12 0.001.

o.

:1.24 0.01/' 0.032 0.001 0.759

'1.3

o.oo1. o.oo:L

0.025 0.053 0,:1.13 0.101

1.4 0.001 (),()01. o.o::;o 0.006 0.081 0.062 SUH 1-- 2 :1.0.'768 18,949 24.925 15, 8tH 18.00'7 6.901 f.\UH 3-.. 14 54.0!:17 92 + 5:~3 1.28.37-l 171.822 196.B41 135.889 TOTAL 64.B55 U1,4B2 15~L 299 1El7 + 673 214.848 142.790

- 22 -

Tab le

1.3

Weight at ageJ in grammes Icelandic summer spawners

1969 - 1981.

Rings ^{1. 96~1} 1.970 :1.971 1972 1973 1974 197~'5

::i:::.o

El~i. o B8.0 96.0 90.0 80.0 110.0

:l!S? ·)O 1.69.0 16:';, o 1"/7,0 1.9'7'.0 189.0 179.0

.. :l; lS·'~)~O 216.0 2:0,() ::.~78. o 2~'!7. o 262,0 241 .o

4 264.0 26:3.

o

^{27~~ ~o ~·-n2.0} 27B,O 297.0 291

.o

5 2El4. o 3l210 301

.o

^3::0!8,0 337.0 340.0 319.0 b 304.0 3:.;~9. o 324.0 379.0 381 .o 332.0 339.0

_, ;:>;:w.o :nB,O 346. () 410.0 380.0 379.0 365.0

l

B ::~;'?2.

o

3:'!7.0 3b8.0 419.0 397.0 :~:Oi6 +o 364.0

7' :379. o 37f.l.O ~5¹90'

o

470.0 385.0 407.0 407.0 lO ;390 '('• 3S>6,0 409.0 ~)00. o 450,0 410.0 :389.

o

11. 376.() 40B.O 412.0 ~iOO, O 4~.'i0. o 410.0 430.0

:1. ;~ 401..0 4~~::,:;. o 420.,() 500.0 450.0

4n.o

^416.0

13 409,0 430.0 442.0 ~500. o 450.0 423.0 416.() :1.4 414.0 4~:;o. o 4:'iO,O 500.0 4!=iO.O 423.0 416.0 Rings J.976 1.977 1.9?8 1.979 1.980 1981.

l 1.03.0 f:14,0 73.0 ^{?~':j .. ··~} 68.9 60,f) :z: I.B9, O :1.57.0 128.0 :1.45.:1 l.1:'.'i. 3 140.9

~~ 243.0 :~:1. 7'

o

196.0 182.4 202.0 190. !:'i 4 281. ^,(i 2·~)1 to 247.0 23(),9 232.5 245.~j

~s 3(J~5. () 2B~:; ~O 29~-=.i + () 21:!4.,7 268. ~) 268.6

(".} 3:3::~ ~o ~31.~~~0 314.0 31~5.7 316.7 297.6

7 351 _'

o

326.(J ~5~19. o 33:<. 7 3~.'11 i[, 329.8 8 35!:} ~o 347.0 T59.0 ^3~)(~, 4 360.4 355.7 9 ~W~i.O 364,() _~~60 ·!o :~61.)' 7 ~f79 + 9 368. :~

to 36;~~. o 362.0 3'?.~ .. ,o ;:::6a. :3 382.9 405.4 J l 3<?6 ,() ~5~5~~ to 3f~O. O :·:S'/0.6 ~592. 7 381 +~.i

l? ^{~~~}/:: )()} J!:.i~.i ~ () 42~.i.O ~~f.jQ +o 390. o 400.0

n ^{~~..;-... :.'(l} 400,0 -425.0 350.0 390.0 400.0

l 4 39/; ~o 420.() .. f2::i.:O 450.0 ~~90 + () 400.0

- 23 -

Table 4•4 Echo abundance estimate rmillions of herring) Jan.1982 age distribution, mean length and weight at age

Winter rings Echo abundance Age dis tri- l

w

X 10- 6 bution %

1 5 1 14.2 20

2 23 3 21.9 86

3 99 12 26.'2 143

l+ 206 24 28.8 181

5 54 6 31.4 236

6 157 18 32.0 256

7 205 24 33.3 291

30 3 34.5 324

9 10 1 34.5 324

10 57 7 35.8 352

10+ 12 1 36.8 390

Weight in

tonn es X 10- 3 ₂₀₄

- 24 -

Tab le ~·2

Calculated fishing mortality, Icelandic Summer Spawners

1969

-

1981. M= 0.10,

Initial

F

( 4+) =

^0.20

Rings

1969 19"70 19"71 1972 197;?:: l974 19?5 0.1.08 0.04'1' 0.1.24 0.003 o.ooo o.ooo o.ooa 2 0.844 0.966 o' 44:~ 0.006 0.003 0.009 0.019

3 ^o.~i68 1, OO~:i o. ~i?8 o.oo? (),014 0.015 0.084

4 0.655 0.61.4 :1..463 0.032 0.006 0.020 ^{().l ~j~j}

~5 0./15 0,/?5 0.999 0.090 (),003 o.oo~; o .196 6 0.827 0.713 :J.,331 0.036 0.005 0.009 o.O!'.:i6

? 0.920 0.850 1.858 0.068 (),004 0.001 0.101

B 0.901. 1. 01~! 3.066 0.055

o.olA

0.001 0.1.44

9 o.B5? 1.?2? 2.373 0.617 0.00? 0.003 0.102

1.0 1.149 0.655 2.03f.l (),(:)!;:;2 o.2:?~i 0.002 0.012 11. :1..219 0.867 o.9B9 0.343 o.O?/ 0.097 O, OO~:s

1.2 1' :1.10 :I .• :W4 (), ^01.~i 0.01.6 O, L~O o. 120 0.120 1.3 0.799 3.564 ^o.o3~i o.ot:,9 O.OHl () .1.~!2 o .152 14 0.700 1.000 :1 .• ooo 0.040 0.020 0.020 0.200 AVERAGE !.>JEIGHTED

BY

STOCt\ IN NLJNBEF~S

AVE 3-··U 0.693 0.915 :t.212

o.

02~i 0.011 0.015 0.098 AVE 4·-·14 o. 7~'i0 0,744 1..474 o. 0~'!4 0.006 o. ^01~i o .14~j

Rings

₁₉₇₆ 1977 197f.l :1.979 1.'1'80 1981

l 0.001. 0.001 (),01.9 (),()02 0.009 0.006 2 0.066 0.031 o. ^0~:04 0.1.33 0.043 O, Ol.4 3 0.043 o. 1.91 o. lO:?. o. :1.38 ^o.2~i4 o ^.o~;6 4 O. :I.l? 0.131 (),1.47 ().l 77 0.246 o.:wo

!.:) 0.20:?. 0,19:?. 0.142 0.232 0.234 o. ^~:!00

6 o .1. 9~5 (),:?.54 •),22B ()' 168 0.237 o.:wo 7 O, OB~:i 0.250 0.4~".)2 o' ~:~0(.) 0.280 0.200 8 o. 133

o.

:1.32 0.470 0.289 0.219 0.200 9

o.:uo

o. :1.94 0.204 0.217 ^0.2~)8 0.200 10 0.1.61 0.269

o

^t ~555

o.oso

^o t24'? 0.200

1.:1. o.~~71 0.03? 0.4B4 r),492 (), 144 0.?00

12 0.003 1..034 0.028 0,057 0.002

o.:oo

13 o. 1.::'i2 0.003 o. ~i20 {).:1.02 0.261 0.200

14 0.200 0.200 o.2oo 0.200 0.200 0.200

AVEF~fiGE WEIGHTED

BY

BTOCK IN NUI-1BEF;:s

AVE 3--13 0.1.1.4 O.JB8 0.152 0.1.73

o.

~~40 0.154

A'JE 4-14 0,131 0,186 0.216 o.:t90 0.238 0.200

- 25 -

Tab le ~.6 Stock in numbers, millions, Icelandic Summer Spawners

1969 - ^{1981. M = 0.10,}

^{Initial F}

^{( 4+)} = ^0.20

Rings 1969 1970 1971 1972 1973 1974 197~i

1 46.312 44.331 79.056 71.917 494.879 123.B29 185.555 2 143.544 3} ^l 61.1 38.209 63.199 64.906 448.402 112.031 3 19.980 ~5.845 12.954 22.190 56.819 58. ~i66 402.230 4 11 .. 264 10.249 1.8.499 6.5?4 19.929 50.714 52.219 5 20,474 5.2(?5 5.016 3.876 5.763 17.925 44.964 6 5.2}1 9.0~i9 2.208 1.672 3.207 5.198 16.134

7 2.408 2.086 4.020 o.52B 1.460 2.888 4.660

B 2.071 0,868 0.806 o' ~.'i6? 0.446 1..315 2.611 9 1 ^f 104 0.761 0.285 (!,034 0.486 0.398 1.189 :LO 0.646 0.424

o.

123 0.024 0.016 0.437 (),359

1.1 0.422 0.185 0.199 0.014 0.011 0.011 0.394

l2 0.216 (), l.13 0.071 0.067 0,009 0.009 0.009 13 0.207 0.064 0.031 (),063 0.060 (),007

o.oo?

14 0.154 0.084 (),002 0.027 0.053 ^l), 053 0.006 Adult stock

10.9 24.3

^l.fb.2

135.4

weight

3-14 16.9 21.1 12.3

Rings 1976 1977 1978 19?9 1980 1981

688,!:128 49:3 ~ 2~i2 1.42.014 412.55~¹ 38S·. 460 428. ti30

.t:,.', 166.~)05 622.678 445.6.:'>5 12l>t021 T/2,425 349.319

3 99.490 1.41.02} ':i46. 058 :!,.EJ:~. 043 99.847 ^3:~2. 94.?

4 ~~~H. 635 06.199 10~.i.~~93 44b.147 :301 ^t 01.2 70.069 5 41.298 ;·~69. 408 !:i8.422 82t350 ~::38.210 213.053 6 33.444 30 .~)20 201.134 53.698 ~59.073 242.210

} 13.807 24.906 21.425 144.901 41.073 42.1?9 B ~~, B:l..l 11.471 ^{1 .. 7} c:·r"7

, / .".} .... } ... ^} 12' 58~'i 106.667 28.098

7' 2.047 ~L020 9.095 ? • 9~0:7 8. ~i27 '7"? + 523 :1.0 (l. CJ?t 1. ,'562 2. 2~i0 6 •. 712 /',228 5.961.

l.1 l)' ~521 o., ?48 1·081 ].,1.69

:i.

608 5, 11.0

1. :;.~

o

^{t ~55b} 0.201 0.652 0.603 0.647 4.393

13 0.007

o.

^{3~!1 O, O.S~i}

o.

^~571.\

o.

^~i15

o.

~j8~3

14 0.006 0.006 o.2B9

o.

^{0~~~5 0.469 0,359}

Adult stock

234.9 272.8 261.5 267.0

weight

3-14 149.6 153.7

Table 5.1 The monthly catch, from the Icelandic cape lin stock in weight and numbers by nations, August 1981 - March 1982

Catch in tons X 10- 3 Catch in numbers X 10- 9

Month Iceland Norway Faroes EEC Total 1980 1979 1978 1977 Total

August 31.4 91.4 9.7 12.4 144.9 + 6.4 0.8 + 7.2

September 66.4

-

6.5 8.4 81.3

o.

1 4.2

o.

3 + 4.6

October 151.3

-

- - 151. 3 + 7.7 0.2 + 7.9

November 187.4 -

- -

^187.4

o.

2 8.4

o.

5

-

9. 1

December 48. 1 - - ^{48. 1}

o.

1 2. 5 0.1 + 2.7

Jan/March 13.

o -

- 13.

o

+ 0.6 +

-

0.6

/\) Cl'\

Total 497.6 91.4 16.2 20.8 626.0 0.4 29.8 1. 9 + 32.1

- 27 -

Table 5.2

The total annual and seasonal catch from the Icelandic capelin stock 1971 -1982 (tons x 10-3

)

Winter season Summer and autumn season

Year Iceland Faroes Iceland Norway Faroes EEC Total

1971 182.9 182.9

72 276.5 276.5

73 440.9 440.9

74 461. 9 461. 9

75 457.6 3. 1 460.7

76 338.7 114.4 45 3. 1

77 549.2 25.0 259.7 833.9

78 468.4 38.4 497.5 154. 1 1.158.4

79 521.7 17.5 441.9 126.0 2. 5 1.109.6

1980 392.0 367.2 118.6 24.4 14 l 3 916.5

81 156.0 484.6 91.4 16.2 20.8 769.0

82 13.

o

- 28 -

Table 5,3

Stock abundance in nmnber and weight by yearclasses and maturity 1 November 3-131 1981.

Yearclasses

1980 inm. 1979 inm. 1979 mat. 1978 mat. Tat mat.

Nx10-9 Tx10-3 Nx10-9 Tx10-3 Nx10-9 Tx10-3 Nx10-9 Txl0-3 Nx10-9 Tx10-3 2.7 13.8 1.4 17.8 16.6 316.9 0.3 7.5 16.9 324.4

Table

5.4

Stock abundan.ce in number and weight by yearclasses and maturi t:Y 1 Noverrber 26-29 1981.

Yearclasses

1980 .inm. 1979 inm. 1979 mat. 1978 mat. Tat. mat.

Nx10-9 Tx10-3 Nx10-9 Tx10-3 Nx10-9 Tx10-3 Nx10-9 Tx10-3 Nx10-9 Tx10-3 21. o 76.0 1.1 13.5 11.9 230.4 0.6 13.5 12.5 243.9

Table 5.5

Stock abundance in nurnber and weight by yearclasses and maturity 1 January ll-221 1982.

Yearclasses

1980 inm. 1979 imn. 1979 mat. 1978 mat. Total mat.

Nxl0-9 Tx10-3 Nx10-9 Tx10- 3 Nx10-9 Tx10-3 Nx10-9 Tx10-3 Nx10-9 Tx10- 3 l.G 12.6 1.6 18.7 6.9 135.5 0.5 12.7 7.4 158.2

Table 5~

Stock abundance in nurnber and weight by yearclasses and maturity₁ February 1982.

Yearclasses

Area 1980 irnm. 1979 imm. 1979 mat. 1978 mat. Total mat.

Nx10-9 Tx10-3

Nx10-9 Tx10-3

Nx10-9Tx10-3 Nx10-9Tx1o-3 Nx10-9Tx10-3 NE-reel.

E-Icel. 2.3 16.0

0.2 3.2 4.1 50.4

0.9 16.3 1.2 20.9

+ 0.8 0.2 2.7

0.9 17.1 1.4 23.6

- 29 -

Table 5.7

Spawning stock abundance in mmber and weight, Jan.-Febr. 1982.

Yearclasses

1978 Total

1979

Nxl0-9 Txl0-3 Nxl0-9

Txl0-3 Nxl0-9 Txl0- 3 8.4 160.9 0.6 14.8 9.0 175.7

Table 5.8

The total catch from the Icelandic capelin stock in weight and numbers during periods between successive acoustic abundance estimates in 1981- 1982.

Catchin Catch in numbers numbers and weight by yearclasses

Period Txl0-3 Nxl0-9 1980 1979 1978 1977

August-oct. 23 358.0 17.7 O.l 17.3 1.3 +

Oct. 24-Nov. 12 124.2 6.1 O.l 5.7 0.3

Nov. 12-Nov. 29 76.6 3.7 O.l 3.4 0.2

Nov. 30-Jan 22 54.2 3.0 O.l 2.8 O.l

Total 613.0 31.5 0.4 29.2 1.9 +